Wis. Admin. Code Department of Safety and Professional Services SPS 34.06
If any owner or employee of an agency is responsible for the accidental or intentional discharge of any firearm other than in target practice, competition, or licensed hunting, or is responsible for the accidental or intentional use of deadly force by any means, the owner or employee shall immediately after the incident notify the local law enforcement agency where the incident took place and inform his or her supervisor of the incident. The supervisor or another person assigned by the agency shall investigate the incident as soon as possible, and shall make a signed, written report of the incident, identifying all persons involved in the incident, the investigator, and the agency, and fully describing the circumstances of the incident. As soon as possible after the investigation is completed, a copy of the report shall be filed with the department and with the local law enforcement agency.
Wis. Admin. Code Department of Safety and Professional Services SPS 34.06